Map (Manifold Air Pressure) Sensor - Mercury MerCruiser D2.8L D-Tronic Service Manual

EDI DIAGNOSIS

MAP (Manifold Air Pressure) Sensor

Scan Code:
Blink Code:
Malfunction Indicator Lamp:
a
CIRCUIT DESCRIPTION:
The MAP (Manifold Air Pressure) sensor and IAT (Intake Air Temperature) sensor form an
assembly. The MAP sensor portion of this assembly is a pressure transducer that measures
the changes in the intake manifold pressure. The pressure changes as a result of engine
load and speed change, and the MAP sensor converts this to a voltage output signal from
the assembly.
NOTE: Sometimes this component may be referred to as a boost pressure sensor due to
the presence of a turbocharger.
The ECM sends a 5 volt reference signal to the MAP sensor. As the manifold pressure
changes, the electrical resistance of the MAP sensor also changes. By monitoring the
sensor output voltage, the ECM knows the manifold pressure. A higher pressure, low
vacuum (high voltage) requires more fuel, while a lower pressure, higher vacuum (low
voltage) requires less fuel. The ECM uses the MAP sensor to control fuel delivery and
injection timing.
A failure in the MAP sensor circuit should set a Scan Code P0105.
40
41
55
Page 5E-20
a - MAP / IAT Sensor Assembly
b - IAT Signal
c - 5 Volt Reference Signal
d - MAP Signal
e - Sensor Ground
f - To Throttle Position Sensor
CKT PIN
MAP Signal
5 Volt Reference Signal
Sensor Ground (–)
SERVICE MANUAL NUMBER 22
P0105
2222
ON
GRN/BLK
GRN
WHT/YEL
BLU/WHT
f
NAME
90-860074--1 FEBRUARY 2002
b
64
c
41
d
40
e
55
75340